This invention pertains to the aircraft control and display art and, more particularly, to a system providing a quickened flight path angle display for use in conjunction with a computer augmented manual flight path angle control system to overcome poor handling qualities due to intrinsic flight path angle response lags.
Such a controlled system, referred to as a "Velocity Vector Control Wheel Steering System" (VCWS) is disclosed in U.S. Pat. No. 4,373,184, issued Feb. 8, 1983, invented by the same inventor as the present application, and assigned to the same assignee. This system allows a pilot to input a commanded flight path angle .gamma..sub.C via his control column, with this commanded flight path angle being captured in a well-damped, overshoot free way.
FIG. 1 illustrates the indicator 10 used in association with the flight control system in the above-referenced velocity control wheel steering system patent. The principle feature of the display 10 is that simultaneous indications 30, 32 represent both the flight path angle command .gamma..sub.C and the aircraft's actual flight path angle .gamma., respectively.
Various pitch lines 24-26 are indicated on the screen along with a reference airplane symbol 28.
A landing system glide slope indicator 16 is provided with an appropriate scale indicated generally at 18.
A roll pointer 12 indicates roll attitude relative to a suitable roll attitude scale, indicated generally at 14.
A landing system localizer indicator 20 is provided with an appropriate scale indicated generally at 22.
During tracking conditions in the VCWS mode both symbols overlay. The value of the flight path angle is read against the pitch scale. The pitch attitude is determined by the airplane symbol position relative to this scale, with a 5.degree. noseup bias being applied to unclutter the symbology. For example, when flying level, the flight path angle wedges 30, 32 overlay and point at the 0.degree. (horizon) line 33. During a column input, the response of the .gamma..sub.C symbol 30 leads the .gamma. symbol 32 in proportion to the amplitude of the column input (and thus .gamma..sub.C). When the column input is returned to neutral, the actual flight path angle .gamma. closes in on the commanded flight path angle .gamma..sub.C in a quick and well-damped way.
Whereas the above-described display provides a positive means for indicating to the pilot his commanded, as well as actual flight path angle, further research in the development of a suitable display configuration for the velocity control wheel steering system has indicated that a single symbol containing the pertinent information of both .gamma. and .gamma..sub.C is desirable. Such a single symbol would reduce the number of symbols presented to the pilot, thus tending to unclutter the display to the pilot, as well as preventing the possibility of the pilot confusing the actual flight path indicator with the commanded flight path indicator, and inadvertenly deviating from a desired flight course.